Pressure sensors having ceramic platforms are applied for measuring pressures. Among these pressure sensors are absolute pressure sensors, which measure the absolute pressure acting on the measuring membrane relative to vacuum, relative pressure sensors, which measure the pressure acting on the measuring membrane relative to a reference pressure, such as e.g. the current atmospheric pressure, supplied to the pressure measuring chamber, as well as pressure difference sensors, which register a pressure difference between a first pressure acting on a first side of the measuring membrane and a second pressure acting on a second side of the measuring membrane.
Pressure sensors are widely applied in almost all fields of industrial measurements technology. Ceramic platforms offer the advantage that they are not only thermally, chemically and mechanically very resistant, but also have a very high pressure resistance. Pressure sensors having ceramic platforms must be mounted at the location of use and be supplied via corresponding process connections or pressure supply lines, depending on sensor type, with the pressure to be measured, the pressure to be measured plus the reference pressure, respectively the two pressures, whose difference is to be measured.
For this, pressure sensors are applied e.g. in housings equipped with process connections, or in another manner connected with process connections and/or pressure supply lines. Housings, process connections and pressure supply lines are regularly built of metal, e.g. stainless steel.
The ceramic platform is, thus, regularly mechanically connected with at least one metal body via a pressure-tight connection.
In such case, there is the problem that ceramic has a thermal coefficient of expansion, which significantly differs from the thermal coefficient of expansion of the usually installed metal body. Ceramic materials have a thermal coefficient of expansion, which typically lies in the order of magnitude from 5 ppm/K to 8 ppm/K. In contrast, stainless steels have a clearly higher thermal coefficient of expansion in the order of magnitude above 16 ppm/K.